Protective effects of carboxymethyl chitosan-dialdehyde glucan/polydopamine carrier-delivered Bacillus subtilis on the intestinal tract of mice infected with Salmonella.

This study investigated the protective effects of carboxymethyl chitosan-dialdehyde glucan/polydopamine carrier-delivered Bacillus subtilis (PBS) on Salmonella-induced intestinal inflammation in mice. The results indicated that PBS significantly lowered the organ index and inflammatory factor levels while increasing the levels of oxidase in mice. Interestingly, after PBS intervention, the mRNA expression levels of mucin, tight junction proteins, immune proteins, and transcription factors that constitute the intestinal barrier in mice exhibited a significant increase compared to those in the model group. The intestinal flora results showed that PBS improved the abundance of Ruminococcus, Bacillus, and Roseburia, simultaneously increasing the content of short-chain fatty acids. Furthermore, the downstream protein expression of pathway genes confirmed that PBS inhibited the inflammatory response by regulating the TLR4-NF-κB-NLRP3 inflammasome signaling pathway. These results indicate that carrier protection for Bacillus subtilis can enhance its relief effect on mice infected with Salmonella.